I've been looking for a new wide angle for a full frame Nikon. The obvious choice is of course the 14-24mm f/2.8, but it's too expensive for me right now.

So I've been looking at the Samyang 14mm f/2.8 as I don't really need the zoom. But before I go spend my money on something I'd like to hear from you guys if you might've bumped into some cool wide angle I didn't know existed

This is not really new, but you can consider the Ais F2.8 20mm or the AF F2.8D 20mm. You can get a good used one for about $550 on ebay. Mechanically, the Ais feels a lot more robust but both lens use the same optics. So image quality is the same.

The two wide lenses I use on my d700 are the nikkor 20mm 1:2.8 ais and the Tokina 17mm f/3.5 sl ais.

Both are older manual focus lenses, which doesn't matter much since focus is not very critical on such a wide lens. Tokina makes a newer af version of the 17mm, but I doubt it's worth the extra $.

Both of these would be considered "budget" alternatives, as the nikon cost less then $300, and the tokina only around $150.

Between them I'd recommend the nikon, as it shoots nice sharp images with good contrast at f2.8, whereas the tokina doesn't match the nikon's IQ until f5.6. I'd take the extra two stops over the extra 3mm of wider focal length.